


Burn Faster

by whoawicked



Category: Undertale (Video Game)
Genre: Ecto-Penis (Undertale), Ecto-Tongue (Undertale), F/M, Heatfic, Knotting, Mating Bites, Mating Cycles/In Heat, Rough Sex, Sans is very sweaty, Vaginal Fingering, Vaginal Sex
Language: English
Status: Completed
Published: 2017-03-23
Updated: 2017-03-23
Packaged: 2018-10-09 14:14:16
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,040
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10414002
Author URL: https://archiveofourown.org/users/whoawicked/pseuds/whoawicked
Summary: Sans is in heat, and you told him you'd help out.{ A short little drabble for Mikrebyle, who was lucky enough to win the raffle I did on myNSFW/+18 tumblrfor reaching 100 followers!  I hope you like it. >w< }





	

**Author's Note:**

  * For [Mikrebyle](https://archiveofourown.org/users/Mikrebyle/gifts).



> This ran a little bit longer than I said it would, but that's okay. I've actually almost hit 200 followers since running the raffle, so thanks to everyone that followed! uwu

Sans was sweaty.  Too sweaty.  You didn’t mind. 

 

You told him you would help, after all.

 

“god, you’re just so…  _fuck.”_

His voice was shuddering, his breath feeling like hot steam against your lips as his phalanges wouldn’t stop clutching your sides, running up and down your absolutely gorgeous curves.  His hands searched for purchase, but never lingered in one spot for too long—almost as if he couldn’t decide where to keep them.

 

His hot tongue fucked your cute little mouth, filling it up with his magic, in and out, in and out.  You struggled to breathe through your nose, but you could take it.  He knew that.

 

Your arms were slung around his cerebral vertebrae, holding on to him as he grinded his cock against your fleshy inner thighs.  He was rough and without respite—his silky precum slathering your skin in its popping, fizzing magic. 

 

“p-please,” he groaned into your mouth.  “please, i need ya, kiddo.”

 

His teeth locked your lower lip between them, his jaw trembling with desire as he struggled to control how hard he bit down.  His sharpened canines hurt.  You liked it.  You _loved_ it.

 

You felt the heat in his bones, and you felt it in your slicked pussy.  Your breathing was quickening, trying to keep up with how hard your heart pumped blood and adrenaline through your veins.  Your mind clouded with lust—nothing but the overwhelming desire to _fuck him_.

 

You hurriedly nodded your consent. 

 

Sans growled into your mouth as he gave a particularly strong thrust into your thigh.  It was animalistic and carnal, sending a sharp wave of pleasure down your spine. 

 

You felt cold as he pulled up and away from you, grabbing your ankles and yanking you closer to him.  You squealed in surprise, but he didn’t bat an eye socket.  He was too focused on your beautiful, dripping pussy.  He thumbed at the little nub protruding from under its hood, and you jerked your hips from the sudden direct contact. 

 

“F-Fuck, Sans, that feels— _Ah!”_

 

Two boney fingers slipped inside you abruptly, all the way up to his knuckles.  You keened as the sweaty skeleton watched his fingers slide in and out of your dripping cunt, the wetness forcing lewd squishing noises with each of his thrusts. 

 

His face was contorted into a lazy grin, fixated on your delicate pussy, and his cheek bones were dusted with deep cerulean as his left eye socket flashed with lust.  You allowed your gaze to focus on his heaving ribcage, the bones thrumming with the same magical color. 

 

You briefly wondered if a monster heat was painful.

 

Sans continued to scissor inside your pussy, spreading his fingers, opening you up for him.  He was quite well-endowed, and your skeleton lover knew that you needed quite the preparation in order to take him (mostly) painlessly.

 

You don’t know if he actually thought you were ready or if he just ran out of patience when he removed his fingers from you and licked them clean.  His tongue was long and tapered, twirling around his phalanges with dexterity that was reminiscent of a tentacle.

 

“you taste so sweet, babe,” he told you through a husky growl, but he was too busy positioning his cock head at your entrance care to listen if you answered him.  He looked down at you with struggling restraint. 

 

“c-can i?” he stuttered. 

 

You wrapped your legs around his lower spine, and he needed no other encouragement before slipping inside you with one smooth thrust. 

 

You both keened and groaned from the sensation of filling your tight little cunt.  Despite the prep work, you still struggled to fit his girth, your walls fluttering and squeezing him like a vice. 

 

Sans fell over you as he worked up a steady pace inside you, covering your neck and shoulders in nips and bites—maybe a bit rougher than you would have liked.  You felt a stinging pain as he sunk his sharpened teeth into the juncture of your neck and shoulder, but you were too stimulated to care if he drew blood.

 

His pelvis smacked into your inner thighs as he fucked you hard and steady into the mattress.  Your hands gripped between the rungs of his ribs to steady yourself, and he _snarled_ at you.

 

“yes, keep—touching—me!”

 

You complied.  Your fingers squeezed and gripped around his bones, feeling almost like a white-hot porcelain.  He growled again, deep and guttural, and you felt your orgasm already swelling in your core.

 

Or—

 

Wait—

 

Is that—

 

A knot?

 

You felt the swollen bulge ram into your battered pussy over and over again, only feeling larger and larger with each consecutive thrust.  You bore down on him from the realization, feeling this sick and twisted desire to take his knot like _you_ were the one in heat.

 

Sweat dripped from his skull as he squeezed his eye sockets shut. 

 

“’mm close, s-so close—“

 

You keened and writhed when, after one strong thrust, he forced the beginning of his bulging knot inside your cunt.  You struggled to take it in, but you were determined to placate his heat. 

 

You bit your lip and squeezed his bones harder in your hands as he continued to cram the knot inside you.  It was hot—so hot it almost felt like it was burning you with his magic—and just this side of painful.

 

You moaned his name, and all he could do was growl at you in response.

 

“’mm gonna—“

 

He tried to warn you before bottoming out inside your pussy, the entire knot situated well within your warm cunt.  He grunted and stilled his erratic thrusts, sinking his teeth into your shoulder one last time before releasing his magic seed deep within your belly.  You felt his cock twitch and shudder as he filled you up with his cum for what seemed like hours—how long had it been?

 

The knot kept all of his cum inside you, plugging you up and causing a dim blue glow in your abdomen.

 

You tried to make small talk as you waited for the knot to die down, but Sans had fallen asleep on top of you.

 

This was _knot_ what you signed up for.

**Author's Note:**

> Can't believe this is the first time I've published something with Tale!Sans. Haha, I hope you guys like it. >w<
> 
> Check out my [NSFW tumblr blog](http://whoawickedsins.tumblr.com) filled with juicy skeleton smut and exclusive content! 
> 
> Or my [SFW (mostly) main blog](http://whoawicked.tumblr.com) with other silly things.


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